For this lab you need to get hold of a set of "hot wheels" or similar with a loop attachment. I found these for about 15 Euros a set and I live in Norway so should be available cheaply in most countries. Apart from the track and car you also need a ruler and something to clamp the end of the track to. I stuck tape to the track and marked every cm, I then sent the car down from the highest mark then reduced the height...